April 1, 2017
View Full PaperLeft atrial function and phenotypes in asymmetric hypertrophic cardiomyopathy
Key Result
Left atrial function was impaired in hypertrophic cardiomyopathy, with septal longitudinal strain worsening from -18.5% in controls to -11.6% in severe obstructive phenotypes (P<.05).
Study Design
Type
Observational (n=155)
Multicenter
No
Structured PICO
Is left atrial function impairment associated with disease phenotype severity in patients with asymmetric hypertrophic cardiomyopathy?
P
Population
n=155 individuals from the Stanford Cardiomyopathy Registry, including 50 age-/sex-matched healthy controls, 35 patients with nonobstructive HCM (HCM 1), 35 patients with obstructive HCM (HCM 2), and 35 patients with obstructive HCM requiring septal reduction therapy (HCM 3).
C
Comparator
Healthy controls and different HCM phenotypes
O
Outcome
Left atrial (LA) function including LA emptying fraction and LA strain, and left ventricular (LV) strain measured by echocardiographysurrogate
Left atrial function and septal longitudinal strain are progressively impaired across increasingly severe phenotypes of asymmetric hypertrophic cardiomyopathy.
Main Result
p-value: p=<.05
Abstract
BACKGROUND: Few studies have analyzed changes in left atrial (LA) function associated with different phenotypes of asymmetric hypertrophic cardiomyopathy (HCM). We sought to demonstrate the association of impairments in LA function with disease phenotype in patients with obstructive and nonobstructive HCM. METHODS: From Stanford Cardiomyopathy Registry, we randomly selected 50 age-/sex-matched healthy controls, 35 patients with nonobstructive HCM (HCM 1), 35 patients with obstructive HCM (HCM 2), and 35 patients with obstructive HCM requiring septal reduction therapy (HCM 3). Echocardiography was performed to evaluate left ventricular (LV) strain as well as LA function including LA emptying fraction and LA strain. RESULTS: for HCM 3, and P<.05 all between groups). All measurement of LA function was impaired in patients with HCM than controls. Total and passive LA function was further impaired in HCM 2 or 3 compared with HCM 1, while active LA function was not different among the three groups. Among LV strains, only septal longitudinal strain differed among all groups (-18.5±1.9% in controls, -14.5±1.9% in HCM 1, -13.3±1.8% in HCM 2, -11.6±2.3% in HCM 3, and P<.05 all between groups). CONCLUSIONS: LA function was impaired in patients with HCM even in minimally symptomatic nonobstructive phenotype. Total and passive LA function was further impaired in patients with obstructive HCM.